In vivo methods in both humas and animals have proven valuable in elucidating the pathophysiology of diabetes and cardiometabolic disease, despite some technological limitations. The Animal Physiology Core (APC) has incorporated recent progress in the miniaturization of instrumentationand and increased sensitivity of monitoring devices to provide tools for measurements in intact undisturbed rodents. The APC brings together four experts in the areas of integrative physiology, cardiovascular physiology, imaging, and animal models who serve as a core resource for the study of diabetes using rodent models. The goal of the APC is to provide easy access to highly-specialized equipment and expertise in the area of body composition, energetics, glucose homeostasis, cardiovascular assessment, imaging, and transgenic animal models and technology, to augment diabetes and cardiometabolic research quality and cost effectiveness. The Specific Aims of the Core are: 1. To provide expertise in the use of animal models for diabetes and cardiovascular research; 2. To provide state-of-the-art instrumentation and methodology for the determination of: a. Body composition: Whole-body composition analysis by chemical carcass analysis, dual-energy X-ray absorptiometry (DXA), quantitative magnetic resonance (QMR), Faxitron X-ray, and micro-computed tomography (pCT). b. Energy balance: Comprehensive assessments of metabolic rate (indirect calorimetry), food intake, fecal output, activity, and body temperature. c. Glucose homeostasis: Glucose and insulin tolerance testing and hyperinsulinemic-euglycemic clamps. d. Cardiovascular assessment: Echocardiography and blood pressure. e. Imaging: Bioluminescence, fluorescence, and gamma-ray imaging including SPECT, PET, and MRI. f. Transgenic animal models: Assistance with construct preparation, generation of transgenic/knock-out mice, husbandry and colony management, and genotyping.